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September 16, 2024
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NFC Technology

  • September 16, 2024
  • 1 reply
  • 1938 views

Hello, I have a question: Is the NFC technology in the iPhone always active, even if the Wallet app is not in use? I mean, is it always emitting RF radiation to read/write?

    This topic has been closed for replies.
    Best answer by Ulysses HERNIOSUS

    Hello Jonamleonel,

    I think you need to differentiate two scenarios:

    1. Phone acting as reader writer (poller) to find external cards. In this mode it is periodically emitting pulses to find NFC tags. Constant Carrier is only entered during communication with a card. Typically this polling (also background polling on iPhone) is only entered when the phone is unlocked (on iPhones also when screen is locked but on). To my knowledge no phone is polling in screen-off state.
    2. When talking about wallet it means phone acting as card. In this mode the phone is by its own not emitting any field. Only when providing an answer to an external NFC field modulated command it will for a short time turn on an own field (Active Load Modulation as opposed to NFC cards which are doing Passive Load Modulation). This field emission is pretty much neglectable. This NFC activity is also active when the phone is in Screen Off state.

    About health effects: Due to the low frequency and the low power the consensus is that there is no risk here (even if it would be Constant Carrier.) Constant Carrier is typically avoided to save power.

    BR, Ulysses

     

    1 reply

    ST Employee
    September 16, 2024

    hi JonamLeonel, 

    Yes, NFC RF is always active on iPhone. Even if wallet App is not in use. 
    This allows to handle NFC background reading mode : the system scans for and reads NFC data without requiring users to scan tags using an app. 
    Hope it clarifies.

    br,

     

    Explorer
    September 16, 2024

    Is it always emitting electromagnetic waves/RF ? Is it dangerous for people, many people uses its phones in the pants pockets 

    Technical Moderator
    September 16, 2024

    Well, you may need to ask Apple about the exact circumstances when and how NFC is active.

    By “dangerous for people” do you mean a health risk or a risk to security or finances?

    Regards
    /Peter